Pixel array substrate

ABSTRACT

A pixel array substrate includes a pixel region and a circuit region adjacent to the pixel region. A plurality of display pixel units are disposed in the pixel region and a plurality of dummy pixel units are disposed in the circuit region. Each of the dummy pixel units includes a data line, a scan line, a plurality of switching elements and a plurality of pixel electrodes. The switching elements are electrically connected to the scan line and data line. The pixel electrodes are electrically connected to the switching elements. Particularly, electrostatic currents in the pixel region can be dissipated by the dummy pixel units in the circuit region. The dummy pixel units preserve the continuity of electricity in the pixel array substrate and function as an inner short ring. Therefore, the area of the circuit region on the pixel array substrate is larger.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of and claims the prioritybenefit of U.S. application Ser. No. 12/352,575, filed on Jan. 12, 2009,now allowed, which claims the priority benefit of Taiwan applicationserial no. 97132574, filed Aug. 26, 2008. The entirety of each of theabove-mentioned patent applications is hereby incorporated by referenceherein and made a part of specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pixel array substrate, andparticularly to wherein an area of a circuit region is larger.

2. Description of Related Art

In recent years, with the progressive manufacturing techniques inoptoelectronic and semiconductor fields, flat panel displays are growingrapidly, wherein liquid crystal displays (LCDs) have become themainstream due to its low operating voltage, no radiation, light weightand small volume.

A conventional LCD mainly includes an LCD panel and a back light module,wherein the LCD panel generally comprises a thin film transistor (TFT)pixel array substrate, a color filter (CF) substrate and a liquidcrystal layer disposed therebetween. Intricate circuits and componentssuch as scan lines, data lines and pixel units are formed on the TFTarray substrate by semiconductor manufacturing processes.

FIG. 1 is a schematic diagram of a conventional pixel array substrate.Referring to FIG. 1, a pixel array substrate 100 comprises a substrate110, a plurality of pixel units, and a plurality of scan lines SL anddata lines DL. The substrate 110 comprises a pixel region 112 and acircuit region 114 adjacent to the pixel region 112. The scan lines SLand data lines DL are disposed in the pixel region 112 of the substrate110. An end of each of the scan lines SL and an end of each of the datalines DL extend into the circuit region 114, and are electricallyconnected to elements in a gate driving circuit area 132 and a sourcedriving circuit area 142. Each of the pixel units comprises a TFT 122and a pixel electrode 124, and each pixel unit is electrically connectedto its corresponding scan line SL and data line DL. In addition, pixelunits 120 a disposed in the pixel region 112 have graphic-displayingfunctions, so they are called display pixel units, whereas pixel units120 b disposed in the circuit region 114 are called dummy pixel unitsdue to the fact that they cannot display graphics.

Many electrostatic charges may be accumulated during the manufacturingprocess of the aforementioned pixel array substrate 100, especially whenmanufacturing equipment and operators touch the pixel array substrate100 frequently. Therefore, when the electrostatic charges on the pixelarray substrate 100 are accumulated to a critical amount, anelectrostatic discharging phenomenon would occur.

When an electrostatic discharging phenomenon occurs, important circuitsor elements on the pixel array substrate 100 may be easily damaged.Particularly, electrostatic charges accumulate easily on the ends of thescan lines SL and the data lines DL, making them especially prone topoint discharging. The instantaneous high voltage from point dischargingoften causes short circuits in the scan lines SL and the data lines DL,leading to malfunction of the pixel array substrate 100.

In the prior art, in order to avoid the damages caused by theelectrostatic discharging, it is common to dispose a shorting bar 150 inthe circuit region 114 of the pixel array substrate 100. The shortingbar 150 is serially connected to gate lines and source lines through aplurality of switching elements 152. When the lines or pixel units 120a, 120 b on the substrate 110 are overloaded with electrostatic charges,the switching elements 152 can be turned on to dissipate theelectrostatic charges to the shorting bars 150, in order to avoidelectrostatic discharging. However, this method requires more space fora circuit layout of circuit region 114.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic diagram of a conventional pixel array substrate.

FIG. 2 is a schematic diagram of a pixel array substrate according tothe first embodiment of the present invention.

FIG. 3 is a schematic diagram of a single dummy pixel unit of the pixelarray substrate in FIG. 2.

FIG. 4A is a schematic diagram of an equivalent circuit of the singledummy pixel unit in FIG. 3.

FIG. 4B is a schematic diagram of an electrostatic discharging path whenstatic electricity is transmitted from a scan line.

FIG. 5A is a schematic diagram of a single dummy pixel unit of a pixelarray substrate according to the second embodiment of the presentinvention.

FIG. 5B is a schematic diagram of an equivalent circuit of the singledummy pixel unit in FIG. 5A.

FIG. 6 is a schematic diagram of an equivalent circuit of a single dummypixel unit in a pixel array substrate according to the third embodimentof the present invention.

FIG. 7A is a schematic diagram of a single dummy pixel unit in the pixelarray substrate according to the fourth embodiment of the presentinvention.

FIG. 7B is a schematic diagram of an equivalent circuit of the singledummy pixel unit in FIG. 7A.

FIG. 8A is a schematic diagram of a single dummy pixel unit in a pixelarray substrate according to the fifth embodiment of the presentinvention.

FIG. 8B is a schematic diagram of an equivalent circuit of the singledummy pixel unit in FIG. 8A.

SUMMARY OF THE INVENTION

The present invention provides a pixel array substrate that requiresless space for the circuit region.

The present invention provides a pixel array substrate, which comprisesa pixel region and a circuit region adjacent to the pixel region. Thepixel array substrate comprises a plurality of display pixel unitsdisposed in the pixel region and a plurality of dummy pixel unitsdisposed in the circuit region. Each of the dummy pixel units comprisesa data line, a scan line, a plurality of switching elements and aplurality of pixel electrodes. The switching elements are electricallyconnected to the scan lines and the data lines. The pixel electrodes areelectrically connected to the switching elements. Particularly,electrostatic currents in the pixel region can be dissipated by thedummy pixel units in the circuit region.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units comprises a first switching element, asecond switching element, a first pixel electrode, a third switchingelement, a fourth switching element and a second pixel electrode. An endof the first switching element is electrically connected to the dataline, while the other end of the first switching element is electricallyconnected to one end of the second switching element. The other end ofthe second switching element is electrically connected to the scan line.The first pixel electrode is electrically connected to the first andsecond the switching elements. One end of the third switching element iselectrically connected to the data line, while the other end of thethird switching element is electrically connected to one end of thefourth switching element, and the other end of the fourth switchingelement is electrically connected to the scan line. The second pixelelectrode is electrically connected to the third and the fourthswitching elements.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching elements are all diodes.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching elements are all TFTs, and thegates of the TFTs are electrically connected to the sources or drains ofthe same TFT.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units further comprises a first storagecapacitor and a second storage capacitor. The first storage capacitor iselectrically connected to the first and the second switching elements,and the second storage capacitor is electrically connected to the thirdand the fourth switching elements.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units comprises a common line, a firstswitching element, a second switching element, a first pixel electrode,a third switching element, a fourth switching element and a second pixelelectrode. The common line is disposed parallel to the scan line, and anend of the first switching element is electrically connected to thecorresponding data line or scan line. The other end of the firstswitching element is electrically connected to one end of the secondswitching element, and the other end of the second switching element iselectrically connected to the common line. The first pixel electrode iselectrically connected to the first and the second switching elements,and an end of the third switching element is electrically connected tothe data line. The other end of the third switching element iselectrically connected to one end of the fourth switching element, andthe other end of the fourth switching element is electrically connectedto the common line. The second pixel electrode is electrically connectedto the third and fourth switching elements.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching elements are all diodes.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching elements are all TFTs, and thegates the TFTs are electrically connected to the sources or drains ofthe same TFT.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units further comprises a first storagecapacitor and a second storage capacitor. The first storage capacitor iselectrically connected to the first and the second switching elements,and the second storage capacitor is electrically connected to the thirdand the fourth switching elements.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units comprises a TFT, a pixel electrode, acommon line, a first switching element, a second switching element, athird switching element and a fourth switching element. The TFT iselectrically connected to the data line and the scan line. The pixelelectrode is electrically connected to the TFT. The common line isdisposed parallel to the scan line. One end of the first switchingelement is electrically connected to the data line, while the other endof the first switching element is electrically connected to one end ofthe second switching element, and the other end of the second switchingelement is electrically connected to the common line. One end of thethird switching element is electrically connected to the other end ofthe second switching element and the common line. The other end of thethird switching element is electrically connected to one end of thefourth switching element, and the other end of the fourth switchingelement is electrically connected to the other end of the firstswitching element and the data line.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching electrodes are all diodes.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching elements are all TFTs, and thegates of the TFTs are electrically connected to the sources or drains ofthe same TFT.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units further comprises a first storagecapacitor electrically connected to the TFT.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units further comprises a second storagecapacitor and a third storage capacitor. The second storage capacitor iselectrically connected to the second and the third switching elements,and the third storage capacitor is electrically connected to the firstand the fourth switching elements.

According to an embodiment of the present invention, each aforementioneddummy pixel unit comprises a TFT, a first pixel electrode, a firstswitching element, a second switching element, a third switchingelement, a fourth switching element a and second pixel electrode. TheTFT is electrically connected to the data line and scan line. The firstpixel electrode is electrically connected to the TFT. One end of thefirst switching element is electrically connected to the scan line,while the other end of the first switching element is electricallyconnected to one end of the second switching element. The other end ofthe second switching element is electrically connected to the data line.One end of the third switching element is electrically connected to theother end of the second switching element. The other end of the thirdswitching element is electrically connected to one end of the fourthswitching element, and the other end of the fourth switching element iselectrically connected to the scan line. The second pixel electrode iselectrically connected to the third and the fourth switching elements.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching elements are all diodes.

According to an embodiment of the present invention, the aforementionedfirst, second, third and fourth switching elements are all TFTs, and thegates of the TFTs are electrically connected to the sources or drains ofthe TFTs.

According to an embodiment of the present invention, each of theaforementioned dummy pixel units further comprises a first storagecapacitor electrically connected to the TFT.

According to an embodiment of the present invention, each aforementioneddummy pixel units further comprises a second storage capacitor and athird storage capacitor. The second storage capacitor is electricallyconnected to the second and the third switching elements, and the thirdstorage capacitor is electrically connected to the third and the fourthswitching elements.

In the pixel array substrate of the present invention, the dummy pixelunit further has the function of providing protection againstelectrostatic discharging. Therefore an additional electrostaticdischarging protection element in the circuit region is not required.This increases flexibility in the circuit layout of the circuit region.

In order to make the aforementioned and other objects, features andadvantages of the present invention more comprehensible, severalembodiments accompanied with figures are described in detail below.

DESCRIPTION OF EMBODIMENTS First Embodiment

FIG. 2 is a schematic diagram of a pixel array substrate according tothe first embodiment of the present invention. Referring to FIG. 2, apixel array substrate 1000 comprises a substrate 110, a plurality ofscan lines SL and data lines DL, a plurality of display pixel units 120a and a plurality of dummy pixel units 1200. The substrate 110 comprisesa pixel region 112 and a circuit region 114 adjacent to the pixel region112. The scan lines SL and data lines DL are disposed in the pixelregion 112 of the substrate 110. An end of each of the scan lines SL andan end of each of the data lines DL extend into the circuit region 114,and are electrically connected to elements of a gate driving circuitregion 132 and a source driving circuit region 142. Each of the displaypixel units 120 a comprises a TFT 122 and a pixel electrode 124, andeach of the display pixel units is electrically connected to thecorresponding scan line SL and the corresponding data line DL.

In addition, the pixel array substrate 1000 further comprises aplurality of dummy pixel units 1200. The dummy pixel units 1200 aredisposed on at least one edge of an area where the display pixel units120 a are located. More specifically, the aforementioned dummy pixelunits 1200 may be disposed in the area between the display pixel units120 a and the gate driving circuit area 132, in the area between thedisplay pixel unit 120 a and the source driving circuit area 142, or inboth areas.

In the present invention, the dummy pixel units may be implemented in aplurality of ways. Details are illustrated below.

FIG. 3 is a schematic diagram of a single dummy pixel unit of the pixelarray substrate in FIG. 2. FIG. 4A is a schematic diagram of anequivalent circuit of the single dummy pixel unit in FIG. 3. Referringto both FIGS. 3 and 4A, each of the dummy pixel units 1200 comprises adata line DL, a scan line SL, a first switching element 1230, a secondswitching element 1240, a first pixel electrode 1280, a third switchingelement 1250, a fourth switching element 1260 and a second pixelelectrode 1290.

Accordingly, an end 1232 of the first switching element 1230 iselectrically connected to the data line DL, while the other end 1234 ofthe first switching element 1230 is electrically connected to one end1242 of the second switching element 1240. The other end 1244 of thesecond switching element 1240 is electrically connected to the scan lineSL. In addition, the first pixel electrode 1280 is electricallyconnected to the first switching element 1230 and the second switchingelement 1240.

Accordingly, one end 1252 of the third switching element 1250 iselectrically connected to the data line DL, while the other end 1254 ofthe third switching element 1250 is electrically connected to one end1262 of the fourth switching element 1260, and the other end 1264 of thefourth switching element 1260 is electrically connected to the scan lineSL. In addition, the second pixel electrode 1290 is electricallyconnected to the third switching element 1250 and the fourth switchingelement 1260.

According to the present embodiment, the first switching element 1230,the second switching element 1240, the third switching element 1250 andthe fourth switching element 1260 are all TFTs, and the gates of theTFTs are electrically connected to the sources or drains of the sameTFT. In other embodiments, the first switching element 1230, the secondswitching element 1240, the third switching element 1250 and the fourthdevice electrode 1260 may also all be diodes or other switchingelements.

In addition, each of the dummy pixel units 1200 further comprises afirst storage capacitor Cs₁ and a second storage capacitor Cs₂. Thefirst storage capacitor Cs₁ is electrically connected to the firstswitching element 1230 and the second switching element 1240, while thesecond storage capacitor Cs₂ is electrically connected to the thirdswitching element 1250 and the fourth switching element 1260. The firststorage capacitor Cs₁ and the second storage capacitor Cs₂ are formed bystacking parts of a common line CL, the first pixel electrode 1280 andthe second pixel electrode 1290 in one of the dummy pixel units 1200,respectively. In the present embodiment, the common line CL is shaped asan H, but the present invention is not limited to the said arrangement;other shapes may also be used. In addition, the first storage capacitorCs₁ and the second storage capacitor Cs₂ may also be formed by stackinga pixel electrode and a scan line (not shown), which is so called acapacitor on gate (Cst on gate).

By utilizing the aforementioned first switching element 1230, the secondswitching element 1240, the third switching element 1250 and the fourthswitching element 1260 of the dummy pixel unit 1200, a plurality ofinner short rings (ISRs) may be formed. The ISRs can effectivelydissipate electrostatic discharges and protect the pixel array substrate1000.

In detail, when the electrostatic current S is transmitted from the dataline DL, the first switching element 1230 and the second switchingelement 1240 will be turned on, so that the electrostatic current Spasses through the first switching element 1230 and the second switchingelement 1240, and is dissipated from the scan line SL after beingtransmitted from one end 1244 of the second switching element 1240.Therefore, the data line DL, the first switching element 1230, thesecond switching element 1240 and the scan line SL form an ISR thateffectively dissipates the electrostatic current S. It is noted that thefirst storage capacitor Cs₁ which is electrically connected to the firstswitching element 1230 and the second switching element 1240 may provideadditional storage capacity for electrostatic charges, therebyincreasing the efficacy of dissipating electrostatic charges.

In addition, a portion of the electrostatic current S may also passthrough the end 1244 of the second switching element 1240 to the fourthswitching element 1260 and the third switching element 1250, and laterbeing transmitted to the data line DL and dissipated. Therefore, thedata line DL, the first switching element 1230, the second switchingelement 1240, the fourth switching element 1260 and the third switchingelement 1250 may form another ISR to dissipate electrostatic current S.Likewise, by utilizing the second storage capacitor Cs₂ which iselectrically connected to the fourth switching element 1260 and thethird switching element 1250, additional storage capacity forelectrostatic charges is obtained, thereby increasing the efficacy ofdissipating electrostatic current.

FIG. 4B is a schematic diagram of an electrostatic discharging path whenstatic electricity is transmitted from a scan line. According to FIG.4B, when electrostatic current S is transmitted from the end of the scanline SL, the fourth switching element 1260 and the third switchingelement 1250 will be turned on, and the electrostatic current S will betransmitted to the data line DL from one end 1252 of the third switchingelement 1250 and will be dissipated. In addition, the second storagecapacitor Cs₂ also stores a portion of the electrostatic charges,thereby increasing the efficacy of dissipating electrostatic current.

In addition, the electrostatic current S transmitted to the data line DLmay also be further transmitted to the first switching element 1230 andthe second switching element 1240, where it passes through the end 1244of the second switching element 1240 to the scan line SL and bedissipated.

Accordingly, a plurality of ISRs formed by the first switching element1230, the second switching element 1240, the third switching element1250 and the fourth switching element 1260 of the dummy pixel unit 1200effectively dissipates electrostatic current and protects the pixelarray substrate 1000. Particularly, because the dummy pixel unit 1200also has the same function as the ISR, an additional ISR is not requiredto be disposed in the circuit region on the pixel array substrate 1000.This decreases the wiring area of the circuit region on the pixel arraysubstrate 1000.

It is noted that when an opposite substrate and the pixel arraysubstrate 1000 are assembled to form an LCD panel, the first pixelelectrode 1280 and the second pixel electrode 1290 of the dummy pixelunit 1200 on the pixel array substrate 1000 will respectively form afirst liquid crystal storage capacitor and a second liquid crystalstorage capacitor (not shown) with pixel electrodes on the oppositesubstrate. The present embodiment should be comprehensible to those ofordinary skills in the present art.

Second Embodiment

The present embodiment is approximately identical to the firstembodiment, and same or similar reference numerals used in the presentembodiment and in the first embodiment represent the same or similarelements. Here in the present embodiment a display pixel unit and adummy pixel unit 2200 on a pixel array substrate are disposed inapproximately the same ways as in the first embodiment, so a relevantdescription is omitted.

FIG. 5A is a schematic diagram of a single dummy pixel unit of a pixelarray substrate according to the second embodiment of the presentinvention. FIG. 5B is a schematic diagram of an equivalent circuit ofthe single dummy pixel unit in FIG. 5A. Referring to both FIGS. 5A and5B, each of the dummy pixel units 2200 of the present embodimentcomprises a data line DL, a scan line SL, a first switching element2230, a second switching element 2240, a first pixel electrode 2280, athird switching element 2250, a fourth switching element 2260, a secondpixel electrode 2290 and a common line CL.

According to the present embodiment, the common line CL is disposedparallel to the scan line SL, and an end 2232 of the first switchingelement 2230 is electrically connected to the data line DL, whereas theother end 2234 of the first switching element 2230 is electricallyconnected to one end 2242 of the second switching element 2240. Theother end 2244 of the second switching element 2240 is electricallyconnected to the common line CL. In addition, the first switchingelement 2230 and the second switching element 2240 are electricallyconnected to the first pixel electrode 2280. A corresponding stackingarea of the first pixel electrode 2280 and the common line CL forms afirst storage capacitor Cs₁, and the first storage capacitor Cs₁ iselectrically connected to the first switching element 2230 and thesecond switching element 2240.

Accordingly, an end 2252 of the third switching element 2250 iselectrically connected to the data line DL, while the other end 2254 ofthe third switching element 2250 is electrically connected to an end2262 of the fourth switching element 2260. The other end 2264 of thefourth switching element 2260 is electrically connected to the commonline CL. In addition, the third switching element 2250 and the fourthswitching element 2260 are electrically connected to the second pixelelectrode 2290. A corresponding stacking area of the second pixelelectrode 2290 and the common line CL forms a second storage capacitorCs₂, and the second storage capacitor Cs₂ is electrically connected tothe third switching element 2250 and the fourth switching element 2260.

The data line DL, the first switching element 2230, the second switchingelement 2240, and the common line CL are electrically connected to forman ISR. In detail, when an electrostatic current S is transmitted fromthe data line DL, the first switching element 2230 and the secondswitching element 2240 will be turned on. The electrostatic current Smay then be transmitted from the first switching element 2230 and thesecond switching element 2240 to the common line and be dissipated.

In addition, the first switching element 2230, the second switchingelement 2240, the third switching element 2250, the fourth switchingelement 2260 and the data line DL may also form an ISR to achieve thefunction of dissipating electrostatic current. In detail, a portion ofthe electrostatic current S may also be transmitted from the fourthswitching element 2260 and the third switching element 2250 to the dataline DL and be dissipated.

Similarly, the first storage capacitor Cs₁ and the second storagecapacitor Cs₂ may store a portion of electrostatic charges, therebyincreasing the efficacy of dissipating electrostatic currents.

Third Embodiment

The present embodiment is approximately identical to the secondembodiment, and same or similar reference numerals used in the presentembodiment and in the second embodiment represent the same or similarelements. A description of the same elements is therefore omitted.

FIG. 6 is a schematic diagram of an equivalent circuit of a single dummypixel unit in a pixel array substrate according to the third embodimentof the present invention. Referring to FIG. 6, the difference betweenthe present and second embodiment is that one end 3232 of a firstswitching element 3230 is connected to a scan line SL.

When an electrostatic current S is transmitted from the scan line SL,the electrostatic current S is transmitted through the first switchingelement 3230 and the second switching element 2240 to a common line CLand is dissipated. In addition, the electrostatic current S may also betransmitted from the fourth switching element 2260 and the thirdswitching element 2250 to a data line DL and be dissipated.

Similarly, the first storage capacitor Cs₁ and a second storagecapacitor Cs₂ may store a portion of electrostatic charges, therebyincreasing the efficacy of dissipating electrostatic current.

Fourth Embodiment

FIG. 7A is a schematic diagram of a single dummy pixel unit in the pixelarray substrate according to the fourth embodiment of the presentinvention. FIG. 7B is a schematic diagram of an equivalent circuit ofthe single dummy pixel unit in FIG. 7A. Referring to both FIGS. 7A and7B, each of dummy pixel units 4200 of the present embodiment comprises adata line DL, a scan line SL, a first switching element 4230, a pixelelectrode 4280, a second switching element 4240, a third switchingelement 4250, a fourth switching element 4260, a common line 4270 and aTFT 4300.

The TFT 4300 is electrically connected to the data line DL and scan lineSL. The pixel electrode 4280 is electrically connected to the TFT 4300.The common line 4270 is disposed parallel to the scan line SL. One end4232 of the first switching element 4230 is electrically connected tothe data line DL, while the other end 4234 of the first switchingelement 4230 is electrically connected to an end 4242 of the secondswitching element 4240, and the other end 4244 of the second switchingelement 4240 is electrically connected to the common line 4270.

Accordingly, one end 4252 of the third switching element 4250 iselectrically connected to the other end 4244 of the second switchingelement 4240 and the common line 4270. The other end 4254 of the thirdswitching element 4250 is electrically connected to one end 4262 of thefourth switching element 4260, and the other end 4264 of the fourthswitching element 4260 is electrically connected to the end 4232 of thefirst switching element 4230 and the data line DL.

Additionally, each of the dummy pixel units 4200 further comprises afirst storage capacitor Cs₁ which is electrically connected to the TFT4300. The first storage capacitor Cs₁ is formed by a stacking area ofthe pixel electrode 4280 and the common line 4270.

Furthermore, each of the dummy pixel units 4200 further comprises asecond storage capacitor Cs₂ which is electrically connected to thesecond switching element 4240 and the third switching element 4250, anda third storage capacitor Cs₃ which is electrically connected to thefirst switching element 4230 and the fourth switching element 4260. Thesecond storage capacitor Cs₂ and the third storage capacitor Cs₃ areformed by the respective overlapping areas between the common line 4270and metal line of the second switching element 4240 or the thirdswitching element 4250 and between the common line 4270 and the metalline of the first switching element 4230 or the fourth switching element4260.

When electrostatic current S is transmitted from the data line DL, it istransmitted to the common line 4270 and be dissipated by turning on thefourth switching element 4260 and the third switching element 4250. Inaddition, the electrostatic current S transmitted by the common line4270 may also be transmitted to the data line DL and be dissipated byturning on the second switching element 4240 and the first switchingelement 4230.

Moreover, the second storage capacitor Cs₂ and the third storagecapacitor Cs₃ may provide extra storage capacity for electrostaticcharges, thereby increasing the efficacy of dissipating electrostaticcurrents.

Note that in FIG. 7A, the design of the TFT 4300 and the pixel electrode4280 located in the lower part of the dummy pixel 4200 is the same asthat of the display pixel unit 1100. This achieves continuity ofelectronic characters.

Fifth Embodiment

FIG. 8A is a schematic diagram of a single dummy pixel unit in a pixelarray substrate according to the fifth embodiment of the presentinvention. FIG. 8B is a schematic diagram of an equivalent circuit ofthe single dummy pixel unit in FIG. 8A. Referring to both FIG. 8A andFIG. 8B, each of the dummy pixel units 5200 comprises a data line DL, ascan line SL, a TFT 5300, a first pixel electrode 5280, a firstswitching element 5230, a second switching element 5240, a thirdswitching element 5250, a fourth switching element 5260 and a secondpixel electrode 5290. The TFT 5300 is electrically connected to the dataline DL and scan line SL. The TFT 5300 is also electrically connected tothe first pixel electrode 5280.

One end 5232 of the first switching element 5230 is electricallyconnected to the scan line SL, while the other end 5234 of the firstswitching element 5230 is electrically connected to an end 5242 of thesecond switching element 5240. The other end 5244 of the secondswitching element 5240 is electrically connected to the data line DL.

Accordingly, one end 5252 of the third switching element 5250 iselectrically connected to the other end 5244 of the second switchingelement 5240. The other end 5254 of the third switching element 5250 iselectrically connected to one end 5262 of the fourth switching element5260, and the other end 5264 of the fourth switching element 5260 iselectrically connected to the scan line SL. In addition, the secondpixel electrode 5290 is electrically connected to the third switchingelement 5250 and the fourth switching element 5260.

Moreover, each of the dummy pixel units 5200 further comprises a firststorage capacitor Cs₁ electrically connected to the TFT 5300. The firststorage capacitor Cs₁ is formed by the stacking area of the first pixelelectrode 5280 and a common line 5270. Similarly, the first storagecapacitor Cs₁ may also be formed by a stacking area of the first pixelelectrode and the scan line (not shown), as a Cst on gate.

Furthermore, each of the dummy pixel units 5200 further comprises asecond storage capacitor Cs₂ which is electrically connected to thesecond switching element 5240 and the third switching element 5250, anda third storage capacitor Cs₃ which is electrically connected to thethird switching element 5250 and the fourth switching element 5260. Thesecond storage capacitor Cs₂ and the third storage capacitor Cs₃ areformed by the respective overlapping areas between the common line 5270and metal line of the second switching element 5240 or the thirdswitching element 5250 and between the common line 5270 and the metalline of the third switching element 5250 or the fourth switching element5260.

When electrostatic current S is transmitted from the scan line SL, itmay be transmitted to the data line DL and be dissipated by turning onthe first switching element 5230 and the second switching element 5240.In addition, the electrostatic current S transmitted to the secondswitching element 5240 may also be transmitted to the scan line SL andbe dissipated by turning on the third switching element 5250 and thefourth switching element 5260.

Certainly, the second storage capacitor Cs₂ and the third storagecapacitor Cs₃ may provide extra storage capacity for electrostaticcharges, thereby increasing the efficacy of dissipating electrostaticcurrents.

Additionally, in FIG. 8, the design of the TFT 5300 and the first pixelelectrode 5280 located in the lower part of the dummy pixel 5200 is thesame as that of the display pixel unit 120 a in FIG. 2. This achievescontinuity of the electronic characters.

In summary, the dummy pixel unit of the present invention comprises aplurality of switching elements, and the corresponding connectionsbetween the switching elements and the data line, scan line and commonline form the dummy pixel unit that has the function of electrostaticdischarging protection. Therefore by utilizing the dummy pixel unit assuch, the purpose of protecting display pixel units in the pixel arraysubstrate from damage caused by electrostatic discharging is fulfilled.In addition, since the dummy pixel unit readily provides electrostaticdischarge protection, no additional shorting bars or other ISRs arerequired to be disposed in the circuit region of the substrate. Thisdecreases the wiring area in the circuit region of the pixel arraysubstrate, therefore reducing the size of the pixel array substrate.Furthermore, under the consideration of not changing the size of thepixel array substrate, since no additional shorting bars or other ISRsare required to be disposed in the circuit region of the substrate, thearea for laying circuits in the circuit region on the pixel arraysubstrate is increased. This promotes flexibility of circuit layout inthe circuit region.

Although the present invention has been described with reference to theabove embodiments, application of the present invention is not limitedto these embodiments. It will be apparent to one of ordinary skills inthe present art that modifications to the described embodiment may bemade without departing from the spirit of the invention. Accordingly,the scope of the invention will be defined by the attached claims andnot by the above detailed descriptions.

What is claimed is:
 1. A pixel array substrate, having a pixel regionand a circuit region adjacent to the pixel region, the pixel arraysubstrate comprising: a plurality of display pixel units, disposed inthe pixel region; and a plurality of dummy pixel units, disposed in thecircuit region, each of the dummy pixel units comprising: a data lineand a scan line; a plurality of switching elements, electricallyconnected to the data line and the scan line; and a plurality of pixelelectrodes, electrically connected to the switching elements, whereinelectrostatic currents in the pixel region are dissipated by the dummypixel units in the circuit region, wherein each of the dummy pixel unitscomprises: a thin film transistor, electrically connected to the dataline and the scan line; a pixel electrode, electrically connected to thethin film transistor; a common line, disposed parallel to the scan line;a first switching element, one end of the first switching element beingelectrically connected to the data line; a second switching element, oneend of the second switching element being electrically connected to theother end of the first switching element, and the other end of thesecond switching element being electrically connected to the commonline; a third switching element, one end of the third switching elementbeing electrically connected to the other end of the second switchingelement and the common line; and a fourth switching element, one end ofthe fourth switching element being electrically connected to the otherend of the third switching element, and the other end of the fourthswitching element being electrically connected to the other end of thefirst switching element and the data line.
 2. The pixel array substrateof claim 1, wherein the first, the second, the third and the fourthswitching elements are all diodes.
 3. The pixel array substrate of claim1, wherein the first, the second, the third and the fourth switchingelements are all thin film transistors, wherein a gate of each of thethin film transistors is electrically connected a source or a drain ofthe same thin film transistor.
 4. The pixel array substrate of claim 1,wherein each of the dummy pixel units further comprises a first storagecapacitor, electrically connected to the thin film transistor.
 5. Thepixel array substrate of claim 1, wherein each of the dummy pixel unitsfurther comprises a second storage capacitor and a third storagecapacitor, the second storage capacitor being electrically connected tothe second and the third switching elements, the third storage capacitorbeing electrically connected to the first and the fourth switchingelements.